Quebec’s borrowing costs are rising as independence once again becomes an election issue in Canada’s second largest and most indebted province.

Quebec Premier Pauline Marois called this week for an election on April 7 in a bid to turn her minority government into a majority, renewing speculation she will press for a referendum on splitting from Canada. The spread, or extra yield demanded by investors, on Quebec’s 10-year bond over debt from neighboring Ontario has widened 7 basis points to 17 basis points since the Quebec bond was issued in December, data compiled by Bloomberg shows. The spread has widened three basis points since the start of last week.

Investors aren’t “necessarily comfortable with the added political risks on top of the risks that have been associated on an ongoing basis,” David Watt, chief economist at the Canadian unit of HSBC Holdings Plc., said by telephone yesterday from Toronto. “So they lighten up on Quebec a bit, and move into Ontario.”

It would be the third plebiscite on independence in the predominantly French-speaking province since 1980. Quebec came within 54,000 votes of a majority in favor of independence in a 1995 referendum. Separatist sentiment has since cooled and has been stalled in the 30 percent range in recent years.